plugin: add getDominantColour

Replaces wack canvas stuff for ColouredIcon

components/effects/ColouredIcon.qml

@@ -1,5 +1,6 @@
 pragma ComponentBehavior: Bound
 
+import Caelestia
 import Quickshell.Widgets
 import QtQuick
 
@@ -7,77 +8,23 @@ IconImage {
     id: root
 
     required property color colour
-    property color sourceColour
-    property url lastSource
+    property color dominantColour
 
     asynchronous: true
 
     layer.enabled: true
     layer.effect: Colouriser {
-        sourceColor: root.sourceColour
+        sourceColor: root.dominantColour
         colorizationColor: root.colour
     }
 
     layer.onEnabledChanged: {
         if (layer.enabled)
-            canvas.requestPaint();
+            CUtils.getDominantColour(this);
     }
 
     onStatusChanged: {
         if (layer.enabled && status === Image.Ready)
-            canvas.requestPaint();
-    }
-
-    Canvas {
-        id: canvas
-
-        property int retryCount
-
-        implicitWidth: 32
-        implicitHeight: 32
-        visible: false
-
-        onPaint: {
-            if (!root.layer.enabled)
-                return;
-
-            const ctx = getContext("2d");
-            ctx.reset();
-            ctx.drawImage(root.backer, 0, 0, width, height);
-
-            const colours = {} as Object;
-            const data = ctx.getImageData(0, 0, width, height).data;
-
-            for (let i = 0; i < data.length; i += 4) {
-                if (data[i + 3] === 0)
-                    continue;
-
-                const c = `${data[i]},${data[i + 1]},${data[i + 2]}`;
-                if (colours.hasOwnProperty(c))
-                    colours[c]++;
-                else
-                    colours[c] = 1;
-            }
-
-            // Canvas is empty, try again next frame
-            if (retryCount < 5 && !Object.keys(colours).length) {
-                retryCount++;
-                Qt.callLater(() => requestPaint());
-                return;
-            }
-
-            let max = 0;
-            let maxColour = "0,0,0";
-            for (const [colour, occurences] of Object.entries(colours)) {
-                if (occurences > max) {
-                    max = occurences;
-                    maxColour = colour;
-                }
-            }
-
-            const [r, g, b] = maxColour.split(",");
-            root.sourceColour = Qt.rgba(r / 255, g / 255, b / 255, 1);
-            retryCount = 0;
-        }
+            CUtils.getDominantColour(this);
     }
 }

plugin/src/Caelestia/cutils.cpp

@@ -90,3 +90,74 @@ bool CUtils::copyFile(const QUrl& source, const QUrl& target, bool overwrite) co
 
     return QFile::copy(source.toLocalFile(), target.toLocalFile());
 }
+
+void CUtils::getDominantColour(QQuickItem* item) const {
+    this->getDominantColour(item, 128, 128);
+}
+
+void CUtils::getDominantColour(QQuickItem* item, int width, int height) const {
+    if (!item) {
+        qWarning() << "CUtils::getDominantColour: an item is required";
+        return;
+    }
+
+    if (!item->window()) {
+        // Fail silently to avoid warning
+        return;
+    }
+
+    QSharedPointer<QQuickItemGrabResult> grabResult = item->grabToImage(QSize(width, height));
+
+    QObject::connect(grabResult.data(), &QQuickItemGrabResult::ready, this,
+        [grabResult, item, this]() {
+            QImage image = grabResult->image();
+
+            if (image.format() != QImage::Format_ARGB32) {
+                image = image.convertToFormat(QImage::Format_ARGB32);
+            }
+
+            std::unordered_map<uint32_t, int> colours;
+            const uchar* data = image.bits();
+            int width = image.width();
+            int height = image.height();
+            int bytesPerLine = image.bytesPerLine();
+
+            for (int y = 0; y < height; ++y) {
+                const uchar* line = data + y * bytesPerLine;
+                for (int x = 0; x < width; ++x) {
+                    const uchar* pixel = line + x * 4;
+                    uchar r = pixel[0];
+                    uchar g = pixel[1];
+                    uchar b = pixel[2];
+                    uchar a = pixel[3];
+
+                    if (a == 0) {
+                        continue;
+                    }
+
+                    r &= 0xF8;
+                    g &= 0xF8;
+                    b &= 0xF8;
+
+                    uint32_t colour = (r << 16) | (g << 8) | b;
+                    ++colours[colour];
+                }
+            }
+
+            uint32_t dominantColour = 0;
+            int maxCount = 0;
+            for (const auto& [colour, count] : colours) {
+                if (count > maxCount) {
+                    dominantColour = colour;
+                    maxCount = count;
+                }
+            }
+
+            const QColor colour = QColor((0xFF << 24) | dominantColour);
+
+            QMetaObject::invokeMethod(item, [item, colour]() {
+                item->setProperty("dominantColour", colour);
+            }, Qt::QueuedConnection);
+        }
+    );
+}

plugin/src/Caelestia/cutils.hpp

@@ -19,4 +19,7 @@ public:
 
     Q_INVOKABLE bool copyFile(const QUrl& source, const QUrl& target) const;
     Q_INVOKABLE bool copyFile(const QUrl& source, const QUrl& target, bool overwrite) const;
+
+    Q_INVOKABLE void getDominantColour(QQuickItem* item) const;
+    Q_INVOKABLE void getDominantColour(QQuickItem* item, int width, int height) const;
 };